In recent years, a sealed scroll compressor including a compressor unit and a motor unit has been known. In the sealed scroll compressor, the compressor unit includes a partition plate that partitions an inside of a pressure container into a low-pressure chamber and a high-pressure chamber, a fixed scroll and a orbiting scroll are provided in the low-pressure chamber, and the motor unit revolves the orbiting scroll. In the sealed scroll compressor, a boss of the fixed scroll is fitted in a securing hole of the partition plate. Refrigerant compressed in the compressor unit is discharged through a discharge port of the fixed scroll to the high-pressure chamber (for example, see Patent Literature 1).
In the sealed scroll compressor, the pressure around the compressor unit is low, so that the orbiting scroll and the fixed scroll are forced to separate from each other.
Hence, in many sealed scroll compressors, a tip seal is used to improve sealability of the compression chamber formed between the orbiting scroll and the fixed scroll.
Back pressure is preferably applied to the orbiting scroll or the fixed scroll to raise operational efficiency. A technique to improve sealability of the compression chamber, without using a tip seal, by applying back pressure to the fixed scroll to push the fixed scroll against the orbiting scroll is proposed (for example, see Patent Literature 2).
Such a technique, however, may result in overturn of the fixed scroll by gas pressure in the compression chamber.